In recent years, various vehicular systems and devices such as an air-conditioner, a radio/CD/DVD player, a navigation system and the like are controlled by using a manually operated control device. More practically, control information for setting temperature, for a selection of radio stations, or for organizing a navigation route or the like is displayed on a display unit, and a user, i.e., an occupant or a driver of the vehicle, is encouraged to control operation conditions of those systems and devices through, for example, a button in a touch panel on the display unit or the like.
However, the occupant of the vehicle is required to watch the operation conditions represented on the display unit very carefully in order to see the result of his/her control while being involved in, for example, a driving operation of the vehicle. In other words, an arbitrary arrangement of the buttons and/or indicators on the display unit may not be very easy to read in terms of readiness for control result recognition unless the occupant are familiar with the arrangement of the buttons and/or representation of the control result.
In view of the above-described problems, disclosure in US Patent Document U.S. Pat. No. 6,593,667 describes a technique of “Haptics,” or a reaction force control technique in response to an operation position of the control device and/or a situation of a control operation. This technique controls a manual operation of a control interface of various devices by providing a reaction force to the interface according to an operation position, an operation condition or the like. The disclosure of the above document also describes an application of a thrusting force in addition to the reaction force.
More practically, the application of the reaction force works in the following manner. That is, Haptics technique provides resistance to restrict a volume-up control operation of, for example, a radio/CD player by applying a reaction force when the user operates a manual operation volume control switch on the CD player, and provides assistance to facilitate a volume-down control operation of the manual operation volume control switch by applying a thrusting force to facilitate the volume-down control. In this manner, a sudden burst of a large sound by mistake is prevented when the occupant controls the volume switch toward a greater sound volume, or a sharp decrease of large sound is achieved for providing a conversational environment in the vehicle based on the thrusting force for the volume down control. The control operations such as the volume-up/down control or the like assisted by the Haptics technique are implemented differently depending on the object device (e.g., the air-conditioner, a navigation system, an audio player etc.). The object device itself of the control operation is changed by operating the control device.
The manually operated control device may be intuitively and/or easily operated when the user remembers respective positions of assigned functions. However, the operation may not be very easily when the user is not familiar with the device or when the user has never operated a similar device. That is, the user may have a hard time for finding an appropriate operation position for executing the respective functions in trials and errors.
Further, the control device may be vocally controlled based on recognition of user's voice in an interactive dialogue with the control device. However, the user can not expect a quick response from the vocal control, thereby suffering from discrepancy between an intended level of control for, for example, a sound volume based on the sound volume actually sensed by the user and a result of the vocal control. That is, the user may feel discomfort due to the discrepancy caused by a delay of the vocal control for the sound volume.